1. Technical Field
Embodiments of this invention relates to an image forming apparatus, such as a copy machine, a facsimile, a printer, etc., and a process cartridge used in the image forming apparatus.
2. Related Art
In general, in an image forming apparatus, a surface of a latent image bearer such as a photoconductive drum, etc., is charged uniformly by an electric charging device to have a desired potential thereon. Subsequently, an electrostatic latent image is formed by irradiating the surface of the latent image bearer bearing the above-described electric charge with a light beam. Then, a toner image is formed by applying toner to the electrostatic latent image. Subsequently, the toner image formed in this way on the latent image bearer is either indirectly transferred onto a recording medium via an intermediate transfer member or directly transferred onto the recording medium, thereby ultimately forming a toner image on the recording medium. Toner residue left on the surface of the latent image bearer is then removed by a cleaning unit after the toner image is transferred therefrom.
In a conventional system, a drum-shaped latent image bearer is employed, and an electric charging roller is provided as an electric charging device to contact the drum-shaped latent image bearer while moving its surface. A cleaning blade is also provided in the conventional system while contacting a surface of the drum-shaped latent image bearer. In such a system, since a surface of the latent image bearer is relatively rarely degraded by electrical discharge applied thereto during an electric charging process when compared to a system that employs a non-contact electric charging device, the contact-type system is more preferable for the latent image bearer when used for a long time. Also, in general, a system that employs a cleaning blade that contacts a surface of a latent image bearer as a cleaning unit can effectively remove toner and clean the surface of the latent image bearer even with a simple structure.
Because it is now important, to downsize the image forming apparatus, a latent image bearer is accordingly downsized. For example, to reduce the weight of the latent image bearer, a drum-shaped cylindrical base material is thinned.
Further, to form an image on a sheet having a special size (329 [mm]×483 [mm]) slightly larger than an A3 size (JIS: 297 [mm]×420 [mm]) by one size, the latent image bearer is elongated in an axial direction thereof (i.e., widened).